What's my meter telling me?

[highup]

Finally got to use my Ligno mini at a friends house. He has some unfinished oak still in it's original boxes and they have been in the dining room for 6 months or so...... let's call em acclimated.

Went out there to see how clse he was getting for carpet in one room, so I took the meter with me.

The oak pins out at 6% or less........ the meter only goes to 6%, but the readings will not go up one point anywhere I check.

I pinned the plywood and I get 6% 10% to 12%, even 14% in one place.
If the meter is not really designed to measure plywood, how do I interpret and compare the two readings?

The 6% reading in the plywood is in an area where the home owner removed a fireplace and installed new plywood. He used roofing felt under the plywood.

OK, funny story about the rest of the plywood in the house. While doing previous remodeling and repairs, he told me that the 'vapor barrier' between the plywood and the ship lap is old wax coated feed bags.
What's the perm rating of wax coated feed bags?

OK, two questions.

How do I compare the moisture readings of the solid unfinished oak, and the plywood subfloor?

Will Aquabar be sufficient as a vapor barrier so the flooring can be laid? It won't be started for a month or three.

 

[Ernesto]

So what your looking for is an average of like 20 to 30 readings of subfloor/underlayment and the flooring. I'd say the highest readings need further investigation, specially if it is solid going down. Can you access the bottom of the plywood? Whats under there?


I'll email you a doc.

 

[highup]

So what your looking for is an average of like 20 to 30 readings of subfloor/underlayment and the flooring. I'd say the highest readings need further investigation, specially if it is solid going down. Can you access the bottom of the plywood? Whats under there?


I'll email you a doc.

I'll check, but I know it's a long road to get under the house to that area. Weather is not cooperating and I'm just there right now to install some crown molding on his cabinets.
I will ask him more about the access to under the house.

Thanks, I appreciate the info a lot. I'll probably be assisting him when he gets ready to nail down the floor, so I just want to steer him right so it comes out good.
It's a 2 1/2 inch solid 3/4" with a micro bevel, so I guess it just takes a gentle surface sanding before finishing.

 

[Nick]

I would go with a 60 grit paper ,the a 80 , and last a 80 grit screen to remove the scratches sandpaper puts in the wood .

 

[Dan]

What meter do you have? Did you get a manual with it? Most have a species correction table in the manual.

 

[highup]

I would go with a 60 grit paper ,the a 80 , and last a 80 grit screen to remove the scratches sandpaper puts in the wood .

The guy is an electrician by trade, but does excellent automotive bodywork, so I'll pass on the info.

What meter do you have? Did you get a manual with it? Most have a species correction table in the manual.

Mine is just an old, used Ligno mini with two ranges. It's pretty basic, but it was also just $35

I need to look up the readings tho. Even with a new battery, it sometimes lights up 3 LEDs when checking the plywood.

Not sure what might cause that to happen.
In the solid wood tho, it might blink between two LEDs or light up two LEDs.

 

[highup]

What meter do you have? Did you get a manual with it? Most have a species correction table in the manual.

My concern Dan, is what am I actually reading when checking the plywood, and how do I compare the plywood reading to the hardwood reading? Aren't they supposed to be within 4% of each other?

There is no specific listing for "plywood" on the Ligno Mini species card.

Solid wood is solid wood........... plywood is layers separated by thin bands of adhesive. If the pins read through 2 or three layers.
........ I am wondering how to compare the plywood readings with the solid wood readings to come up with a ratio between the two materials. ....if there is a way.
...or, do I consider the two readings close enough to make a decision?
6% on the hardwood and 12% to 14% on the plywood are a ways off.

 

[woodguy]

I have a ligno. 6% is fine unless the job is on the ocean. That is a normal reading for a dry subfloor also. The Aquabar will do fine. I use 40 60 100 and screen with 60 again for a drum sander, skip the 60 grit screen if using a belt sander, then screen with 100. I get by with 60 -100 on the edger. make sure the subfloor is flat before laying it. Saves a lot of sanding.

 

[highup]

I have a ligno. 6% is fine unless the job is on the ocean. That is a normal reading for a dry subfloor also. The Aquabar will do fine. I use 40 60 100 and screen with 60 again for a drum sander, skip the 60 grit screen if using a belt sander, then screen with 100. I get by with 60 -100 on the edger. make sure the subfloor is flat before laying it. Saves a lot of sanding.

The flooring won't require aggressive sanding. It's got a micro-bevel ans is already sanded........ it will just need a gentle cleanup sanding before finishing.
I don't think I was clear about that part. The flooring looks like it would pass without any sanding from what I cansee.
.....I bet it just needs the grain to be knocked down if anything.

 

[Nick]

Just hit it with a 80 grit screen then .

 

[Ernesto]

The flooring won't require aggressive sanding. It's got a micro-bevel ans is already sanded........ it will just need a gentle cleanup sanding before finishing.
I don't think I was clear about that part. The flooring looks like it would pass without any sanding from what I cansee.
.....I bet it just needs the grain to be knocked down if anything.

Now thats the way to buy wood. I like manufacturers pre-sanding the wood. Then you can do anything you want to it without some dodo coming in with a drum sander and screwing it up.

I'd push the Rubio Monocoat, course thats more for the greenies. But I know you could do it.

 

[highup]

Now thats the way to buy wood. I like manufacturers pre-sanding the wood. Then you can do anything you want to it without some dodo coming in with a drum sander and screwing it up.

I'd push the Rubio Monocoat, course thats more for the greenies. But I know you could do it.

Me?
I'm possibly gonna play assistant/advisor to help him out. Not sure how long before he's planning on starting the floor, but when it gets closer, I will add another topic so you guys can make me appear smart.

 

[Nick]

Beter to remain silent and appear to be smart , then open your mouth and remove all doubt.

 

[keitht]

I would go with a 60 grit paper ,the a 80 , and last a 80 grit screen to remove the scratches sandpaper puts in the wood

Please forgive the complete newbie question, but what benefit does sanding a subfloor have before you lay hardwood? I figured as long as you were flat that was enough.

 

[woodguy]

Rarely is a subfloor flat. Next time you see one, hold your 6 foot straightedge over one of the seams. You will see for yourself. I always check the seams before installation.

 

[highup]

Please forgive the complete newbie question, but what benefit does sanding a subfloor have before you lay hardwood? I figured as long as you were flat that was enough.

That was referring to the finished floor. The wood is smooth already and has a factory micro bevel. Since the wood is unfinished, it will most likely need a gentle sanding before top coating.